Approach:
Genetic resistance to stem rust will be investigated in cereal crops by selection, breeding and field evaluations, and in grasses by genetic mapping, quantitative trait loci analysis and transcriptome analysis. Molecular markers for stem rust resistance in Lolium will be chosen and validated. Genetic sequences associated with initial response of Brachypodium to the stem rust pathogen will be determined. Greenhouse and field experiments will be used to detect genetic resistance to the choke pathogen in grasses, and to determine whether aphids play a role in the infection process for this pathogen. An epidemic model for stem rust in grasses will be validated and expanded to include overwintering phenomena, and the grass stem rust model will be applied to wheat stem rust by experimental determination of critical parameters in greenhouse and field tests. Field experiments will be used to create a predictive model for infection by the ergot pathogen.